AT1799 2A Step-Down Voltage Regulator Feature 4.75V to 16V Supply Voltage Operating Description AT1799 is a voltage-mode PWM step-down DC-DC converter capable of driving up to 2A Range. over a wide input supply range with excellent 380KHz 15% Fixed Switching Frequency. loads line and load regulation characteristics. High Voltage-Mode PWM Step-Down Regulator. efficiency is obtained through the use of a low Built-in Power MOSFET, Rds(on)100m. Rds(on) P-channel power switch. 2A Output Current, Up to 91.9% Efficiency It uses a fixed switching frequency up to 380KHz 1.215V1.5% Internal Reference thus allowing smaller sized components. The Shutdown Current less than 20uA. output voltage level is user-programmable via an Thermal-Shutdown and Built-in Soft-Start. external resistive voltage divider. The built-in Cycle-by-Cycle Current-Limit Protection. soft-start can reduce inrush current on the input Short Circuitry Protection. source at turn on. Under-Voltage Lockout Protection. Output Voltage Adjustable From 1.215V to The device also has built-in cycle-by-cycle current-limit, thermal shutdown, under-voltage 16V. lockout and an ON/OFF logic-control that can SOP-8 Package. power down the regulator to a shutdown mode. In shutdown mode the regulator draws less than 20uA of supply current. When a short circuit is detected Application on the output , the device immediately change Distributed Power Systems switching frequency to 42 KHz and duty cycle is Battery Charger. limited to 5% to protect IC from damage. Palmtop Computers, PDAs. DSL Modems AT1799 is available in SOP-8 package. Block Diagram Aimtron reserves the right without notice to change this circuitry and specifications. 2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw 8/23/2006 REV:1.1 Email: service@aimtron.com.tw 1 AT1799 2A Step-Down Voltage Regulator Pin Configuration Ordering Information Part number AT1799S AT1799S_GRE Package SOP-8 SOP-8,Green Marking Date Code ,Date Code with one bottom line : Date Code *For more marking information, contact out sales representative directly Pin Descriptions Pin N0. Symbol I/O Description 1 IN P 2 EN I 3 COMP O 4 FB I 5,6 GND P Ground. 7,8 SW O Power Switching Output. Power Input. IN supplies power to the IC and Step-down converter switch. IN must be bypassed with a low-ESR capacitor. Enable input. EN is a digital input that turns the regulator on/off. Drive EN high to turn on the regulator, drive it low to turn it off. Error Amplifier Output. A series RC network connected to this pin compensates AT1799. Feedback Input. Connect a resistive divider from switching output to FB to ground. 2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw 8/23/2006 REV:1.1 Email: service@aimtron.com.tw 2 AT1799 2A Step-Down Voltage Regulator Absolute Maximum Ratings *1 Parameter Rated Value unit IN , EN voltage -0.3 to 16 V SW voltage -1 to IN+1 V FB, COMP voltage -0.3 to 6 V Quiescent current 5 Thermal Resistance (Junction to ambient JA)*2 105 /W Junction Temperature (Tj) 150 Lead Temperature (Soldering 10 sec) 260 Storage Temperature -65~150 HBM 2 KV MM 200 ESD Susceptibility*3 mA V 1. Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. 2. Measured on approximately 1" square of 1 oz. copper FR4 board. 3. Device are ESD sensitive. Handling precaution recommended. The Human Body model is a 100pF capacitor discharged through a 1.5K resistor into each pin. Recommended Operation Conditions Parameter Symbol Min. Values Typ. Max. Unit Power supply voltage IN 4.75 12 16 V Operating temperature Top -20 +25 +85 2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw 8/23/2006 REV:1.1 Email: service@aimtron.com.tw 3 AT1799 2A Step-Down Voltage Regulator Electrical Characteristics (IN=12V, EN=5V, Ta=+25, unless otherwise noted) Parameter Symbol Test Condition Min. Typ. Max. Units 4.75 12 16 V 3.8 4.2 4.6 V - 500 - mV Input operating voltage IN Input under-voltage lockout threshold UVLO hysteresis VUVLO Quiescent Current Iin VFB=1.5V - 3.5 - mA Shutdown Current ISHDN EN =GND - 20 50 uA Oscillator Frequency fSW Ta=+25 - 380 440 KHz FB=0V - 42 - KHz Short-Circuit Frequency IN Rising Feedback Regulation voltage VFB Ta=+25 1.20 FB Input Bias Current IFB VFB=1.215V -50 - 50 nA 2.5 2.75 - A Current limit 1.215 1.233 V Maximum Duty Cycle DMAIN FB=1.0V - - 100 % Minimum Duty Cycle DMIIN FB=1.5V 0 - - % SW Switch On-Resistance RSW-DS(ON) ISW=2A - 100 130 m SW Leakage Current ISW - 0.1 20 A Load Regulation IN=13.5V,VSW=GND , EN=0V 0 A